A bacterial infection is a proliferation of a harmful strain of bacteria on or inside the body. Bacteria can infect any area of the body. Pneumonia, meningitis, and food poisoning are just a few illnesses that may be caused by harmful bacteria. Bacteria come in three basic shapes: rod-shaped (bacilli), spherical (cocci), or helical (spirilla). Bacteria may also be classified as gram-positive or gram-negative. Gram-positive bacteria have a thick cell wall while gram-negative bacteria do not. Gram staining, bacterial culture with antibiotic sensitivity determination and other tests like genetic analysis are used to identify bacterial strains and help determine the appropriate course of treatment.

The expansion of bacterial antibiotic resistance is a growing problem today. When medical devices are inserted into the body, it becomes especially difficult for the body to clear robustly adherent antibiotic-resistant biofilm infections. In addition, concerns about the spread of bacterial genetic tolerance to antibiotics, such as that found in multiple drug-resistant Staphylococcus aureus (MRSA), have significantly increased of late. As a growing direction in biomaterial design, nanomaterials (materials with at least one dimension less than 100 nm) may potentially prevent bacterial functions that lead to infections. As a first step in this direction, various nanoparticles have been explored for improving bacteria and biofilm penetration, generating reactive oxygen species, and killing bacteria, potentially providing a novel method for fighting infections that is nondrug related.

Nanoparticles, which consist of metals such as silver and metal oxides, may be promising agents for antibacterial applications. Additionally, nanoparticles may also have some general mechanism of toxicity toward bacteria that mammalian cells do not have. Nanoparticles bind to bacterial cell walls causing membrane disruption through direct interactions or through free radical production. studies and others determined that nanoparticle antibacterial activity could be mediated by increasing reactive oxygen species (ROS) production, as a result of the use of metal oxide nanoparticles due to metal ion release (which is related to surface area) or through their interaction with ultraviolet (UV) light (which also depends on particle size). The design of orthopedic implant materials for reducing infection could also benefit from the application of nanotechnology. In one study it was found that when ZnO and TiO₂ nanoparticles were pressed into compacts using a cold compaction method, a significant reduction in microbial adhesion was achieved compared with compacts composed of larger micron-sized particles (conventional sizes) of the same respective materials. Another study found that the antimicrobial properties of conventional titanium used in orthopedics could be enhanced through a simple nano-surface modification technique called “electron beam evaporation,” which evaporates TiO₂ using a high-energy electron beam, and allows the material to form on any titanium (Ti) surface; such surfaces were termed “nano-rough.

CONCLUSION

Self-cleaning surfaces based on nanomaterials are already making a significant impact as antimicrobial paints for buildings and hospitals. Although there has been much promise for the use of nanomaterials (whether nanoparticles or nanostructured surface features) to fight infection, it would be remiss not to mention the possible, yet largely unknown, environmental consequences of nanomaterials. In particular, recent research has exposed the possible environmental and toxicological concerns of nanomaterials.